1. Field of the Invention
The present invention relates generally to a vacuum cleaner, and more particularly to a suction head for attachment to the vacuum cleaner, the suction head being applicable not only to hard objects such as wooden floors but also to soft objects such as carpets.
2. Description of the Prior Art
There are various types of known suction heads attached to vacuum cleaners wherein the suction heads are provided with a height adjustment lever such as a pedal for directing the suction nozzle to either a hard object or a soft object as desired.
A typical example disclosed in Japanese Laid-open Patent Publication (Kokai) No. 55-10967 will be explained by reference to FIG. 20. When the cleaner is applied to a hard object such as a wooden floor, the brush 1a is projected beyond a suction head 2a by means of a pedal. In this way the suction head 2a is raised above the floor surface by raising the brush 1a and roller 3a. The distance between the floor surface and the suction port of the suction head 2a is roughly 1.0 mm. This small gap protects the floor surface against becoming scratched by fine dirt such as sand trapped in the bristles.
FIG. 21 shows another example in which a suction head 4a is provided with bristles 5a extending from the suction port. The bristles 5a are made of nylon threads each having a diameter of about 0.15 mm. This type of vacuum cleaner is adapted for cleaning a hard object such as wooden floor and mat (especially Japanese "tatami" mats, which are made of fragile straw and rush). In cleaning "tatami", special care should be paid not to scratch it.
When the Japanese mat ("tatami") is cleaned, the problem is that the woven straws and rush are liable to break by friction caused by the bristles of the brush.
The known cleaners mentioned above have a disadvantage in that the bristles of the brushes scratches the wooden floor panels, sometimes damaging them seriously. Waxed floor panels are especially susceptible to scratches. In addition, the scratchy texture of the floor or carpet is unpleasant for the sweeper, and causes the roller to be noisy. In the case of the Japanese "tatami" mats, the damage becomes more serious.
In order to solve the problems resulting from the bristles of the brushes, soft brushes of fine threads have been proposed. The soft brushes have solved some of the problems but a new problem has arisen. Soft brushes are so pliable that the bristles retain fine particles like food scraps and prevent the particles from entering the dust bag of the cleaner. These fine particles including dirt and food scraps become a breeding ground for germs and ticks. This is unsanitary.